How do I send xml file using curl through http POST request

I have 开发者_开发问答a xml file in my local directory. I need to send this file to the destination url via http POST using curl. I've used following command but this gives me error -

ERROR 2 Data at the root level is invalid. Line 1, position 1.ERROR3 Object reference not set to an instance of an object.%

curl -X POST https://secure.rowebooks.co.uk/testorders/orders.aspx -F file=/Users/sts-108training/Dev/fmn/public/shared/CPI_sample.xml

I'm I missing something?